Frigid temperatures in Europe’s north have heated up Plenum Investment’s energy hedge funds.

Plenum Power Surge soared 19% in January and February. Energy prices in the Nordic region have soared to records, as Sweden suffered the coldest beginning to a year in more than 20 years, while energy consumption set records in Norway.

A second plenum fund, the Plenum Power Fund, returned 6% in the first two months of the year.

“To put it simply, we were bullish on the weather,” portfolio manager Henrik Wennberg told Bloomberg News. “We saw this already in the middle of December and started buying then to take long positions.”